<p>Five artificial neural net simulators that are free of charge, run on Sun Sparcstations under X windows, and are available by anonymous FTP over the Internet, have been tested. The simulators are PlaNet version 5.6 from the University of Colorado at Boulder, Pygmalion version 2.0 from University College in London, Rochester Connectionist Simulator version 4.2 from the University of Rochester, and Stuttgart Neural Net Simulator versions 1.3 and 2.0 from the Institute for Parallel and Distributed High-Performance Systems at the University of Stuttgart in Germany. To compare the simulator's functionality, the number as well as the range of facilities they offer to generating and working with connectionist networks are considered. One artificial neural net was generated with the same topology and functions for all the simulators. A three-layered feedforward net with a backpropagation learning function was used for recognizing printed characters. The test results are discussed.</p>